The present invention broadly relates to the alignment of weapon systems and pertains, more specifically, to a new and improved modular interlinked marine fire-control system. The present invention also relates to a new and improved method of compensating alignment errors in such a modular interlinked marine fire-control system.
Generally speaking, the modular interlinked marine fire-control system of the present development is of the type comprising a plurality of subsystems, each subsystem comprising at least one target detection module and a predetermined number of effector modules operatively associated with the at least one target detection module. The target detection modules and the effector modules are aligned relative to each other and contain means for compensating static and quasi-static alignment errors.
In the practice of the method of compensating alignment errors in a modular interlinked marine fire-control system, there are utilized equipment correction values provided ex-works of the target detection and effector modules and measured values of the coarse position of the installed target detection and effector modules, which coarse position is measured while still in the dock.
The use of fire-control systems on modern warships is allied to the difficulty that, in addition to the deviations dependent on the construction and geometry of the ship or vessel and to equipment tolerances of the target search and tracking units as well as of the effectors, distortions and other temporary deformations are caused during operation by the movements of the ship or vessel due to the motion of the sea, the pitching and the manoeuvring of the ship or vessel. Thus, for example, there can occur a longitudinal bending in a substantially vertical plane, and, if the ship or vessel lists or rolls or does not intersect or cut the waves at a right angle, there can also occur a horizontal bending of the hull. At greater sea forces of 8 to 9, pitching impact may also cause plastic, i.e. permanent deformations. As long as the warships are comparatively small, for example, equipped with only one gun or weapon and a radar, these movements of the ship are not of greater concern. However, on larger ships, in rough sea or during rapid manoeuvring, such movements of the ship may cause considerable elevational movements, and this has an extremely adverse effect on the geometric alignment between the effectors and the target search and tracking units, i.e. the sensor units, and results in errors when the effectors are directed to the target on the basis of the target data determined by the sensor units. These problems become all the more crucial, the greater the distance is between the sensor units and the weapons.
In particular, in the case of large and modern warships, a plurality of effectors, such as launchers and guns, are used nowadays, such effectors being controlled by one or several target measuring systems. These units or installations are distributed across the entire ship and, accordingly, are located at relatively large distances from one another. Therefore, there is a greater need for accurate alignment and compensation of alignment errors under conditions hereinbefore described. This may also result in the fact that corresponding precautions even become a necessity, in order to achieve adequate accuracy of the fire-control system.
The following remarks relating to the object of the present invention as well as the description of the invention are exemplified mainly in conjunction with embodiments comprising guns and radar systems, but they likewise apply to other effectors or weapons and target measuring systems which comprise other sensors such as, in particular, electro-optical target tracking units.
Normally, effectors and target search and tracking units are organized or arranged in subsystems, wherein, for example, per subsystem there are provided one radar and two guns, the two guns being controlled by the radar. These subsystems are arranged at relatively small distances from one another and are mounted at unit or standard type platforms, so that the arrangement can be regarded as quasi rigid. During combat, but also as a result of revision or repair work or material defects, failures in individual equipment units may occur, such failures reducing operational readiness of the associated subsystem or even causing total outage thereof. As a matter of fact, it would then be desirable to couple modules of different subsystems and to make use of theoretical passive redundancy of the overall system. It thus becomes evident that error compensation has to meet requirements which cannot be met by known conventional systems.
In the past, various efforts were made to at least partially overcome the manifold problems of marine fire-control systems. In German Patent No. 3,150,895, published July 14, 1983 and its cognate British Patent No. 2,112,965, published July 27, 1983 there is described a warship, in which static errors are corrected by the control signals of electronic control devices which store the bedding error values of the individual controlling units and controlled units. It is true that by taking into account the alignment errors or bedding errors, the accuracy of the fire-control system can be improved, but dynamic errors caused in action by the movement of the ship while underway are not taken into account. According to these prior art publications, the units or installations are, in fact, partially connected by lines, but for the control of units or installations which are not arranged at a common standard type platform, large deviations between radar and guns occur as a result of dynamic bending effects, such deviations being by no means tolerable. However, notwithstanding the connecting lines, an overall system utilizing passive redundancy has been in no way realized.